I put a new swing and steering outrigger pump on P & H 18. got pump in and cranked it up. Swung the boom back and forth. Did ok. went to extend outriggers and the pump housing cracked. All hoses are right on the pump. Any ideas why it might have cracked ? I know if the hoses are too small in diameter it will crack but I didn't replace any hoses.
Pressure relief valve set too high.
Extending the outriggers should take very little pressure considering you are only pushing the beam outward. How do the controls work on an 18, individual valves for each one, or a selector valve and one spool valve? I would look at the valve that you operated and inspect the hose routing. It takes quite a bit of pressure to split a pump and I would guess a hose on the wrong place or a plugged port that shouldn't be.
Thanks for the info.
What you have is a fixed displacement pump that you have dead headed. Install a relief in between the pump and the valves and you will be fine
If the old pump was leaking , i could understand that some one turned up the relief valve to try to compensate for the bad pump..Just a thought..